One-Way Clutch Decoupler With Fail-Safe Torque Transmission
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Solution Overview
Problem
Existing decoupler systems for alternators face issues with high wear due to friction, require strong and costly materials, suffer from grease leakage, and lack a fail-safe mechanism to continue operating in case of spring failure, limiting their durability and functionality.
Innovation Solution
A decoupler design featuring a pulley with a torsion spring of larger diameter for higher torque capacity, made from lightweight materials without surface treatments, incorporating a fail-safe mechanism with a stop washer to lock the hub pieces in case of overload, and a containment wall to prevent grease leakage, allowing operation as both a free wheel and one-way clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If friction contact between clutch spring and pulley inner race is used for torque transmission, then torque transmission function is achieved, but high wear and component damage occur
Solution Approach 1:
A friction element is introduced as an intermediary component between the clutch spring and the pulley inner race. This friction element absorbs the wear and friction effects, allowing the clutch spring to engage and disengage without direct contact with the pulley, thereby protecting the pulley and clutch spring from damage while maintaining torque transmission capability
Solution Approach 2:
The friction element is designed as a consumable component that can be easily replaced. By making this specific component replaceable and relatively simple, the system allows wear to occur on this inexpensive part rather than on critical components like the pulley or clutch spring, improving overall system reliability
2Strength
If high strength materials and heat treatment are used for pulley to support high stress, then component strength is improved, but weight and cost increase
Solution Approach 1:
The friction element acts as a mediator that protects the pulley from direct contact with the clutch spring, reducing the stress and wear on the pulley. This allows the pulley to be made from lighter materials without requiring high-strength alloys or heat treatment, as the friction element absorbs the mechanical stress
Solution Approach 2:
The invention changes the operational parameters of the pulley by introducing the friction element, which reduces the contact pressure and friction forces acting on the pulley. This parameter change allows the use of lighter materials with lower strength requirements
3Power
If larger diameter torsion spring is used for higher torque capacity, then torque capacity is improved, but internal space requirements increase
Solution Approach 1:
The torsion spring is repositioned from an internal location to an external location on the pulley. By moving the spring to the periphery, the design utilizes the radial dimension rather than consuming axial or internal space, allowing larger diameter springs to be used without increasing the overall package size
4Reliability
If friction element is introduced between clutch spring and pulley, then wear is reduced, but device complexity increases
Solution Approach 1:
The friction element is designed to perform multiple functions simultaneously: it provides torque transmission through friction, protects the clutch spring and pulley from wear, and enables smooth engagement and disengagement. By consolidating these functions into a single component, the overall device complexity is minimized
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces wear, lowers production costs, minimizes grease leakage, and ensures continued torque transmission even if the torsion spring fails, enhancing the decoupler's durability and reliability.
Implementation Method 1
a torsion spring positioned between the outer race of the hub and the inner race of the pulley having a first end operatively couplable to the pulley and a second end operatively couplable to the second hub piece
Implementation Method 2
the clutch spring is arranged internally in relation to the torsion spring and is frictionally couplable to the hub for transmission of torque to the shaft
Data Source
AI summary
The present invention relates to a decoupler with free wheel system and comprising a vibration damping pulley, a shaft actionable by the pulley, hub pieces having a first hub piece and a second hub piece, hub pieces being mounted between the inner race of the pulley and the outer surface of the shaft, at least one journal element between the shaft and pulley, along with a torsion spring, and a clutch spring, with the first hub piece being mounted on the shaft and the second hub piece being mounted around the shaft and can rotate relative to it, the torsion spring being disposed between the outer race of the hub pieces and the inner race of pulley, having a first end operatively attachable to the pulley and a second end operatively attachable to the second hub piece and the clutch spring being disposed internally in relation to the torsion spring and which is frictionally engaged with the hub pieces for transmission of torque to the shaft.